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        검색결과 441

        161.
        2013.10 구독 인증기관·개인회원 무료
        Insect cuticular melanization is regulated by the prophenoloxidase (proPO)- activating system, which is also involved in the innate immune reaction. Here, we demonstrate how the differentiation of the proPO-activating system is regulated toward a cuticular melanization or innate immunity function in silkworm (Bombyx mori) pupae. Our results indicate that the differential and spatial regulation of key components, such as the proPO-activating factor, tyrosine hydroxylase, and porPOs, primes the proPO-activating system for either cuticular melanization or innate immunity. This dual strategy for cuticular melanization in development and innate immunity upon infection demonstrates a two-pronged defense mechanism that is mediated by the priming of the proPO system.
        162.
        2013.10 구독 인증기관·개인회원 무료
        Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03 nM) and proteinase K (Ki 91.53 nM), but not against α-chymotrypsin or typsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, B. thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor.
        163.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The high quality contact between graphene and the metal electrode is a crucial factor in achieving the high performance of graphene transistors. However, there is not sufficient research about contact resistance reduction methods to improve the junction of metal-graphene. In this paper, we propose a new method to decrease the contact resistance between graphene and metal using directly grown graphene over a metal surface. The study found that the grown graphene over copper, as an intermediate layer between the copper and the transferred graphene, reduces contact resistance, and that the adhesion strength between graphene and metal becomes stronger. The results confirmed the contact resistance of the metal-graphene of the proposed structure is nearly half that of the conventional contact structure.
        3,000원
        164.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The performance of graphene-based electronic devices is critically affected by the quality of the graphene-metal contact. The understanding of graphene-metal is therefore critical for the successful development of graphene-based electronic devices, especially field-effect-transistors. Here, we provide a review of the peculiar properties of graphene-metal contacts, including work function pinning, the charge transport mechanism, the impact of the process on the contract resistance, and other factors.
        4,000원
        165.
        2013.04 구독 인증기관·개인회원 무료
        Bacillus thuringiensis (Bt) is a gram-positive bacterium that produces parasporal crystal proteins known as endotoxins or Cry proteins. The Cry protoxins are then cleaved by insect midgut proteinases to form active Bt toxins. The activated Cry protein then binds to specific receptors at the midgut epithelium. Cadherin-like and aminopeptidase N (APN) proteins are involved in Bt toxin binding by interacting sequentially with different toxin structures. Aminopeptidase N (APNs) from several insect species have been shown to be putative receptors for these toxins. We have characterized four different midgut APNs(APN1, APN2, APN3, APN4) cDNAs from S. exigua. Forward primers and reverse primers for confirmation of four different midgut APNs were designed based on their sequences cloned from the cDNA libraries. Quantitative RT-PCR procedures includes 42℃ for 20min (cDNA synthesis), 99℃ for 5min, and 35 cycles (94℃ for 1min, and 60℃ for 50 s) for collection. Four aminopeptidase N isoforms were confirmed with qRT-PCR. Sequence analysis was performed by BlastX search the National Center for Biotechnology Information(NCBI) nucleotide. Furthermore, double-stranded RNAs(dsRNAs) were synthesized. DsRNAs were determined for bioassay.
        166.
        2013.04 구독 인증기관·개인회원 무료
        The green pale plant bug, Apolygus spinolae was one of the main insect pests that damaged leaves and fruit in grapes and its damage status was firstly reported in 2000 in grape orchards. This research was conducted to evaluate the distribution and difference in damage rate depending in management type of grapevine orchards (domestic sale farm vs export farm) in the export complex area of Korea (Hwangsung in Gyeonggii, Sangju and Yeongcheon in Gyeongbuk, Namwon in Junbuk and Yeongdong in Chungbuk) from 2010 to 2012. Damage by A. spinolae occurred in all 62 survey farms and damage rate differed depending on locality and individual farms in the same area. Damage rate was lower in export farms than in domestic sale farms, and damage rate of leaves was highly correlated with damage rate of new shoots. 15 species of hemipteran insect were attracted to sticky traps and A. spinolae was the dominant species. The attracted number of A. spinolae in the sticky traps differed depending on locality, and more occurred in domestic sale farms than expert farms. A. spinolae was continually attracted to sticky traps in the harvest period in grapevine orchards.
        168.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyacrylonitrile (PAN) copolymers of different molecular weights were synthesized by a suspension polymerization and precipitation polymerization method. The rheology behaviors of the synthesized PAN copolymers were investigated in relation to their molecular weight, solid content and melting temperature. The influence of "historical effects" on the spinning solution of PAN was studied by analyzing the laws of viscosity considering the diversification time and temperature. The viscosity disciplines of each spinning solution conformed well to the rheological universal laws in a comparison of the suspension polymerization product with that of precipitation polymerization. Viscosity changes in the swelling process of dissolution were gentler in the suspension polymerization product; a small amount of water will quickly debase the solution viscosity, and high-speed mixing can greatly shorten the time required by the spinning solution to reach the final viscosity.
        4,000원
        169.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylonitrile (AN)-acrylamide (AM) copolymers were prepared by nitric acidic hydrolysis of homopolyacrylonitrile. The acrylamino group increased as a function of hydrolysis time, while crystallinity decreased. Differential scanning calorimetry and a thermal gravimetric analysis indicated that the acylamino introduced by acidic hydrolysis effectively enhanced the cyclization reaction at low temperature due to the change of the cyclization reaction mechanism. Char-yield of AN-AM copolymers also gradually increased with increasing hydrolysis time. The maximum char-yield was 49.48% when hydrolized at 23°C in 65% nitric acid solution for 18 h, which was 30% higher than that of non-acidic hydrolysis of homopolyacrylonitrile. Simulation of the practical process also showed an increase of char yields, where the char yields were 55.43% and 62.60% for homopolyacrylonitrile and copolyacrylonitrile, respectively, with a hydrolysis time of 13 h.
        4,000원
        175.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 베트남 하노이 지역에서 8가지 한국 토마토 품종 (핑크탑, 큐피랑, 슈퍼도태랑, 선레드, 선글러브, TP-7 플러스, 러블리 250, 광복)과 1가지 베트남 품종(FM 120)을 대상으로 봄-여름 및 가을-겨울 작기에 따른 수확량 및 과실 특성을 비교 분석하였으며, 그 결과는 다음과 같다. 1. 작기에 따라 초장, 경장, 주당 과실수 및 수확량(kg)은 유의성이 있었으며 가을-겨울 작기에서 높게 나타났다. 전체적으로 한국품종이 베트남 품종에 비해 높은 생육특성을 보인 반면, 과실수와 수확량에서는 베트남 품종이 우수하였다. 2. 토마토 과실의 주요 특성인 과장, 과폭 및 과중은 작기에 따라 유의한 차이를 보였으며 가을-겨울 작기에서 높은 수치를 나타내었지만 TSS 함량은 봄-여름 작기에서 높았다. 건물중과 비타민C 함량은 작기에 따라 유의한 차이가 없었다. 품종별 과실 특성은 한국 품종이 우수하였지만 비타민C 함량은 베트남 품종이 높았다. 3. 봄-여름 작기에서 한국품종의 경우 수확량 및 과실특성에서 가을-겨울 작기 재배에 비해 큰 감소를 보인 반면 베트남 품종은 큰 차이를 보이지 않았다. 따라서 본 실험에 이용된 8가지 한국 품종의 경우 봄-여름 작기보다는 가을-겨울 작기 재배가 적합할 것으로 판단된다.
        4,000원
        176.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Meedon rice varieties are important for local adaptability, grain quality and market availability, and have been grown in Myanmar for centuries. Because of temporal variability and spatial heterogeneity, Meedon rice varieties in rainfed lowland areas may be diverse. However, information on diversity of Meedon rice germplasm is limited. This study was carried out to assess genetic diversity and to analyze population structure of Meedon rice germplasm conserved in Myanmar Seed Bank using SSR markers. For assessing genetic diversity, 154 accessions of Meedon rice germplasm were analyzed with nine SSR markers. A total of 86 alleles were detected with an average of 9.6 alleles per locus. All the loci were found to be polymorphic, and there were considerable genetic variation among accessions with mean values of expected heterozygosity (HE) = 0.5774 and polymorphic information content (PIC) = 0.5496. High frequency of rare alleles was identified, among which 35 unique (accession-specific) alleles were observed. Based on cluster analysis, rice accessions were mainly clustered into two groups, and as a result of model-based analysis, two distinct genetic populations and an admixture were classified. This result indicated that SSR markers have proved to be useful markers for detecting genetic diversity in Meedon rice, and the occurrence of a considerably high number of rare and unique alleles in the germplasm indicates their potentiality as a reservoir of rare genotypes for use. Unique alleles are also important because they may be diagnostic of a particular type of genotype for identification.
        4,000원
        177.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 반추동물의 조사료 자원으로서 거대억새를 개발하기 위한 목적으로 수행되었다. 우리나라에서 새롭게 개발된 품종인 거대억새 1호를 완숙기 이후에 채취하여 in vitro 반추위 발효를 이용해반추위내 pH, 암모니아태 질소, 가스발생량, 휘발성 지방산 생성량 및 건물소화율을 조사하였으며,볏짚과 비교하여 평가하였다. 거대억새는 볏짚에 비하여 유의적으로 높은 반추위내 pH를 나타내었다(p<0.01). 암모니아태 질소의 경우 배양 12시간 이후에는 두 처리구간의 유의적인 차이를 나타내지 않았다 (p>0.05). 배양 6시간 이후 부터는 거대억새의 가스발생량이 볏짚에 비하여 유의적으로 낮게 나타났다 (p<0.05). 휘발성 지방산 생성량에 있어 acetate, propionate, butyrate, valerate 및 총생상량에서 볏짚이 거대억새보다 높게 나타났다. 그러나 iso-butyrate와 iso-valerate에서는 두 조사료원별 차이는 발견되지 않았다. 건물소화율에 있어 배양 12~24시간 사이의 거대억새 소화율이 볏짚에 비하여 유의적으로 나타났다. 결론적으로 거대억새의 이용성은 볏짚의 약 80% 수준인 것으로 나타났다.
        4,000원
        178.
        2012.06 구독 인증기관 무료, 개인회원 유료
        The influenza virus is an important respiratory risk affecting humans, and effective treatments are needed. Some oriental medicines are currently applied for treatment of common colds as well as influenza infection. Previous studies have reported that the therapeutic properties of MA-128 are effective for treatment of psoriasis antiasthmatic and atopic dermatitis. In this study, we investigated the therapeutic properties of the novel herbal medicine, MA-128, for treatment of influenza virus infection by oral administration. MA-128 is an active natural biological compound from herbal-marine origin. The results showed that oral administration of MA-128 in mice could confer a survival benefit against Type A influenza virus infection. Daily oral administration of MA-128 resulted in delayed death in infected mice for three days against mouse adapted H3N2 (A/Philippines/2/82). However, it protected more than 60% of mice from lethal infection of 2009 pandemic H1N1 (A/Korea/CJ01/2009) influenza virus. In addition, lung viral titers were significantly reduced at seven days post infection (~100 times) compared with mock-treated mice and viruses were cleared at 9 dpi only in the MA-128 treated groups. This study demonstrated the potential of the novel herbal medicine, MA-128, as an herbal remedy against influenza A viruses.
        4,000원
        179.
        2012.06 구독 인증기관 무료, 개인회원 유료
        This study aims to examine the effect of Genetically Modified β -Carotene Biofortified Rice rice developed by simultaneous expression technology in NAAS on biological immunity. Accordingly, this study added Genetically Modified β-Carotene Biofortified Rice 25, 50% and general rice 50% as control group into diet and provided rats with the prescribed feeds and then measured the contents of immunoglobulin and cytokine in blood. As a result, male and female IgM, IgE, male IgG1, female IgG2a and TNF-a, IL5 and IL12 showed no significant difference; male IgG2a tended to decrease dependently on the combined concentration of Genetically Modified β-Carotene Biofortified Rice; female IgG1 showed significance with control group, but its association with diet was not found. The higher the dietary mixing ratio, the more the male and female IFN-a and female IL-4 contents, regardless of rice variety, and it was found that female IL6 content decreased significantly, but its association with diet was not found. The risk of beta carotene-enriched rice into environment and human body has not been reported yet. The digestion of Genetically Modified β-Carotene Biofortified Rice can be seen as "safe" as this test result showed no big difference between general rice and Genetically Modified β-Carotene Biofortified Rice, and its usability is full of suggestions.
        4,000원
        180.
        2012.06 구독 인증기관·개인회원 무료
        Pluripotent stem cells can be derived from both pre- and post-implantation embryos. Embryonic stem cells (ES cells), derived from inner cell mass (ICM) of blastocyst are naïve pluripotent and epiblast stem cells (EpiSCs) derived from post-implantation epiblast are primed pluripotent. The phenotypes and gene expression patterns of the two pluripotent stem cells are different each other and EpiSCs thought to be in a more advanced pluripotent (primed pluripotent state) than mouse ES cells (naïve pluripotent state). Therefore, we questioned whether EpiSCs are less potential to be differentiated into specialized cell types in vitro. EpiSCs were isolated from 5.5~6.5 day post coitum mouse embryos of the post-implantation epiblast. The EpiSCs could differentiate into all tree germ layers in vivo, and expressed pluripotency markers (Oct4, Nanog). Interestingly, EpiSCs also were able to efficiently differentiate into neural stem cells (NSCs). The NSCs differentiated from EpiSCs (EpiSC-NSCs) expressed NSC markers (Nestin, Sox2, and Musasi), self-renewed over passage 20, and could differentiate into two neural subtypes, neurons, astrocytes and oligodendrocytes. Next, we compared global gene expression patterns of EpiSC-NSCs with that of NSCs differentiated from ES cells and brain tissue. Gene expression pattern of brain tissue derived NSCs were closer to ES cell-derived NSCs than EpiSC-NSCs, indicating that the pluripotent stem cell-derived somatic cells could have different characteristics depending on the origin of pluripotent stem cell types. * This work was supported by the Next Generation Bio-Green 21 Program funded by the Rural Development Administration (Grant PJ 008009).